A bound on aperture coupling from realistic EMP

Rigorous modification of the step function electromagnetic pulse (EMP) energy bound, for apertures, to the more realistic description of an EMP waveform is carried out. The double exponential EMP waveform is used first and a general formula is derived for the energy scattered and absorbed by the aperture. This result shows that for very small apertures the energy can be quite small compared to the previous step function result. However, it is indicated that, in principle, if no further conditions are imposed on the structures behind the aperture (or attached to the aperture), the smallest applicable bound is the previous step function bound. Finally, the inverse exponential EMP waveform (with more realistic high-frequency spectrum) is used with very small apertures to obtain even smaller energy bounds than the double exponential waveform result